Field of the Invention
The present disclosure relates to an electrophotographic system image forming apparatus.
Description of the Related Art
In an electrophotographic system image forming apparatus, a configuration is known in which elements such as: a photosensitive drum, serving as a rotating member related to image formation; and a development roller, are formed integrally into a cartridge, which is detachably attachable to an image forming apparatus main body (hereinafter, referred to as an apparatus main body). In such a configuration, since the photosensitive drum in the cartridge is rotated, many apparatuses employ a configuration in which driving force is provided from the apparatus main body.
A configuration that transmits driving force by engaging a driving force transmitting member, which includes a plurality of first engagement portions (engaged portions) on an apparatus main body side, and a coupling member, serving as a driving force receiving member including a plurality of second engaging portions (engaging portions) on a cartridge side, to each other is known.
International Publication No. WO2016/137014A1 discloses a configuration that includes a drive shaft serving as a driving force transmitting member including recesses serving as a plurality of first engagement portions on an outer peripheral surface, and a coupling member serving as a driving force receiving member including a plurality of second engaging portions movable in a radial direction. In such a configuration, driving force is transmitted by having the second engaging portions enter and engage with the recesses (the first engagement portions).
Errors may exist in the driving force transmitting member and the driving force receiving member due, for example, to manufacturing errors. Accordingly, depending on the relative phase relationship between the driving force transmitting member and the driving force receiving member, only some of the first engagement portions and some of the second engaging portions may be engaged with each other. When rotation is performed in such a partially engaged state, since force concentrates on only some of the first engagement portions and some of the second engaging portions, rotational accuracy of the driving force receiving member becomes poor. Accordingly, an image defect may occur during the image-forming period. Furthermore, since force is concentrated on only some of the first engagement portions and some of the second engaging portions, the driving force transmitting member and the driving force receiving member may become damaged.